error[E0428]: the name `MyStruct` is defined multiple times
  --> $DIR/cross-crate-redefine.rs:10:1
   |
LL | my_struct!(define);
   | ^^^^^^^^^^^^^^^^^^ `MyStruct` redefined here
LL |
LL | my_struct!(define);
   | ------------------ previous definition of the type `MyStruct` here
   |
   = note: `MyStruct` must be defined only once in the type namespace of this module
   = note: this error originates in the macro `my_struct` (in Nightly builds, run with -Z macro-backtrace for more info)

error: aborting due to 1 previous error

For more information about this error, try `rustc --explain E0428`.